Redrying of tobacco



Patented Dec. 26,1939 v uNirEo sures ATE-l oFFice REDRYING OF TOBACCOJohn M. Baer, Chicago, 111., assignor to The Guardite Corporation, acorporation of Illinois No Drawing. Application February 26, 1938,Serial No. 192,881

6 Claims. (CI. 34-24) This invention relates to redrying of tobaccoreduced, say, to 50, at which temperature the and more particularly, toredrying of tobacco in tobacco may be discharged. hogsheads. Owing tothe fact that superheated steam is When tobacco is brought into themarket used on all steaming operations, whereas satufrom the farm, it iscustomary for thefarmer to rated steam only is withdrawn by the evacu- 5wait for a moist day so that the tobacco will be ating process, eachstep of the process results in reasonably pliable and capable of beinghandled a reduction of the moisture content, so that the withoutbreaking. This extra moisture, however, final moisture content of thetobacco is substantogether with the natural moisture of the tobactiallybe ow t as Originally At the Same 10 co, frequently renders it unfit forstorage and it time, the tobacco receives the necessary heat 10 istherefore customary to redry th tob cco, treatment for properstabilization of the material This redrying has heretofore been carriedout o S age upon individual leaves of tobacco and not in the Preferably,the operation is carried out in a hogshead, it being customary to heatthe tobacco heated C p a Vacuum ehemin a current of warm air. Thisoperation is exber may be heated by a series of steam coils on 15tremely expensive and involves an excessive the inside of its walls. Theuse of the internal amount of handling. heat to some extent makes up forthe cooling In accordance with this invention, the tobacco y evap rat nut is a s f importance in p is redried while in the original hogsheadand in ventin Condensation 0n the Wells Which ou a very short period.have the effect of partially de-superheating the 20 The redryingoperation is only in part a mat- Steam e p y in the heating y s.

ter of removal of moisture. It also affects the The foregoing detaileddescription has b botanical and chemical characteristics of the v n fcloarness f understanding y, a d tobacco. no unnecessary limitationsshould be understood In accordance with this invention, greentotherefrom. 25 bacon in a hogshead is placed in a vacuum cham- I claim:her and subjected to a vacuum sufliciently high 1. The method ofredrying tobacco which comto boil water therefrom at the temperature ofprises substantially freeing the tobacco from the tobacco until it issubstantially free of nonnon-con-densible gases, heating the tobaccowith so condensible gas. The product may, however, superheated steam toan elevated temperature of be substantially freed of non-condensiblegases at least 140 F. and then cooling the product by in any othersuitable manner. evaporation of contained moisture in a vacuumThereafter highly superheated steam isintroto produce a product of lowermoisture content duced to bring the temperature of the tobacco than theoriginal tobacco.

175 to 200 F.' The tobacco is then cooled by head which comprisessubstantially freeing the subjection to a vacuum and the processrepeated. hege ead from ne -eo s e heating the Preferably, the coolingoperation will not lower tobacco with highly superheated steam to atemthe temperature more than 50 to 75 and the perature of over 175 F.,cooling the tobacco by 40 subsequent steaming with superheated steamevaporation of Contained moisture, again heating 40 will be to a lowertemperature than the initial the product with superheatedsteami tosomewhat lower temperature than the initial For example, the tobacco at60 F. may be'subheating temperature? again cooling jected to a vacuumuntil its tem erature has by i of molsture cooling bemg dropped m 0 Ffollowed by Steaming with carried out until the tobacco is at a lowertem- 45 highly superheated steam to F. The mom perature than after thefirst coollng operation, um is then increased until the temperature hasand repe-atmg the cycl-e the tobacco has a n o substantially lowermoisture content and a final dropped to, say, F. followed by a secondtem erature sub"tantiall of the order of the 50 steaming operation'withsuperheated steam to p b y 9 initial temperature of the tobacco. 50 175h temperature may then be reduced 3. The method as set forth in claim 1in which to S y, y evacuation, felleWed by the operation is carried outin an enclosed zone, t0 With superheated Steam and Subseto the peripheryof which heat is applied indeo n evacuation y, In he next sta pendentlyof the introduced steam during the 55 the temperature may be carried toF. and. operation. 55

so to a much highe temperature, preferably from T e met od of red y gtobacco in a hOgS- with superheated steam to raise the temperaturesubstantially less than the amount the tobacco was previously cooled,and continuing the cooling and heating in this manner until the tobaccohas a temperature approximately atmospheric and a moisture contentsubstantially below the original moisture content.

6. The method as set forth in claim 5, in which the tobacco iscontinuously heated during the process.

JOHN M. BAER.

